1. Field of the Invention
This invention relates to an optical reading device wherein a record medium on which information is recorded optically in accordance with a code system such as, for example, a bar code system is fed in a transverse direction to the direction in which the information is recorded on the record medium in order to read the information, and more particularly to an optical reading device which includes an improved reading mechanism.
2. Description of the Relevant Art
In recent years, as the office automation proceeds, attention is paid to such an optical reading device as disclosed, for example, in European Patent No. 70,697, which can read coded information additionally recorded in the form of a bar code on a record medium and make an automatic dialing operation in accordance with the code information thus read. As the medium for such automatic dialing operation, such a medium as shown, for example, in FIGS. 1, 5 and 10 of British Patent No. 2,063,010 may be employed wherein a telephone number is represented, at a location of a card such as a name card outside an area in which characters are printed, in a bar code representation corresponding to information of the printed characters. An optical reading device can thus read the telephone number and make an automatic dialing operation as shown, for example, in Japanese Patent Laid-Open No. 60-163,154.
Where cards such as name cards have a bar code representation corresponding to formation of addresses and so forth printed thereon, management of the cards can be made sufficiently readily.
While bar code representation systems where name cards are employed as a medium are not yet standardized, it can be sufficiently forecast that, if such systems are standardized and normalized, then name cards on which a bar code representation is printed will come into wide use. As such name cards come into wide use, it is anticipated that demands for code reading devices for reading bar code information on the cards will increase progressively.
An optical reading device for such application normally includes a bar code sensor which includes a light emitting element and a light receiving element, a lens, an optical fiber and so forth in combination. The bar code sensor is moved back and forth in a direction perpendicular to the feeding direction of a name card under the guidance of a screw shaft and a guide shaft. A detecting mechanism which involves such reciprocatory movement is disclosed, for example, in FIG. 1 of Japanese Patent Publication No. 45-13,858 or British Patent No. 1,324,448.
Such a medium in the form of a name card on which a bar code representation is printed at a location other than an area of printed characters thereon in a direction perpendicular to the direction in which it is to be fed in a reading device as described above is inserted in a predetermined direction into an optical reading device. As shown in FIG. 5 of British Patent No. 2,063,010, the name card thus inserted from a lateral side edge thereof is fed by a driving force of a stepping motor or the like installed in the optical reading device while being maintained in a proper orientation until it is stopped at a predetermined position at which the bar code information including a plurality of lines of coded bars is read by such a bar code sensor as described above. With the construction, much information represented on a medium can be read as in such a paper feeding mechanism as is employed, for example, in a well known facsimile apparatus.
Where the bar code representation includes a plurality of lines of code bars, at first the bar code sensor is moved relative to and then scans the first line of code bars, and then a similar operation is successively performed for the second to last lines of code bars, and after completion of the reading operation, the name card is discharged from the optical reading device, similarly as in a well known facsimile apparatus.
By the way, where a bar code sensor has a small size, the depth of focus of the bar code sensor for scanning is shallow. Accordingly, in order to assure a high degree of reading accuracy, it is necessary that the distance between the bar code sensor and a read area of a medium in the form of name card which is to be read by the bar code sensor be maintained stably. However, in such a conventional optical reading device as described above, if it is intended to stabilize the distance between the bar code sensor and such read area of the name card, then the bar code sensor must be maintained at a predetermined height while it is moved back and forth. To this end, the positions in which a screw shaft and a guide shaft are mounted must be specified strictly. Accordingly, a high degree of assembling accuracy is required and deterioration in facility in assembly or increase in production cost cannot be avoided. Further, since name cards have different thicknesses, if a name card inserted in the optical reading device has a thickness greater than a standard one, then the predetermined distance cannot be assured between the bar code sensor and a read area of the name card to be read by the bar code sensor. Consequently, there is the possibility that an error in reading may take place.
Similarly, even a small error of the locations at which the screw shaft and the guide shaft are mounted will lead to an error in height of a path along which the bar code sensor is moved back and forth. Consequently, the distance between the bar code sensor and the area of the name card to be read is unstable, and it is difficult to stabilize the distance. Accordingly, there is the possibility that an error in reading may take place readily, and a degree of accuracy in assembly is required in order to eliminate this. Besides, where there is an error in distance between the screw shaft and the guide shaft which extend through a carrier for the bar code sensor, they cannot guide the sensor carrier smoothly therealong. Also from the point of view, a high degree of accuracy in assembly is required, and deterioration in facility in assembly and increase in production cost cannot be avoided.
It may seem recommendable to stabilize the bar code sensor and the area of the name card to be read by the bar code sensor by resiliently pressing a contact piece of a solid member to be moved back and forth in an integral relationship with the bar code sensor against the medium or name card, for example, in a preceding relationship to the read area of the name card. However, if the solid member the contact piece of which is pressed against the name card is moved together with the bar code sensor, then it may likely damage or soil the read area of the name card to be read. Consequently, there is the possibility that an error in reading may take place contrary to the expectation or that, depending upon a material of the medium, dust may be produced from the medium and stick to a lens of the bar code sensor. Further, if it is attempted to feed the medium while the contact piece is held in resilient contact with the medium, there is the possibility that such feeding of the medium may be disturbed by a frictional force between the medium and the contact piece of the member mentioned above and insertion or discharging of the medium may sometimes be disabled. Besides, a special contrivance is required for eliminating such a possible situation that the contact piece of the solid member to be pressed against the name card may catch the name card and cause a damage to the name card when the name card is inserted into the optical reading device or may obstruct such insertion of the name card.
In addition, in the optical reading device described above, since the sensor carrier contacts with an entire outer periphery of the screw shaft, a load to a motor for driving the screw shaft to rotate is high, and if the sensor carrier is stopped from moving by some causes, then there is the possibility that an overload may be applied to the motor and the motor may fail.